Phosphor and method of making same

ABSTRACT

Electroluminescent phosphors having substantially increased luminance and maintenance over that of prior art electroluminescent phosphors may be made by (1) doping an inorganic intercalation compound having an atomic structure interspersed with vacant spaces, with selected activator ions capable of luminescent emission, and (2) introducing organic monomers or other conductive material into the vacant spaces of the atomic structure of the doped inorganic intercalation compound. The organic monomers may be polymerized in situ to form conductive polymers therein.

The United States Government has rights in this invention pursuant toU.S. Government Contract No. DAAL01-92-C-0241.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 08/162,857,filed Dec. 6, 1993, now U.S. Pat. No. 5,489,398, which is a division ofapplication Ser. No. 08/012,095, filed Feb. 1, 1993, now U.S. Pat. No.5,306,441, which is a continuation-in-part of application Ser. No.07/999,637, filed Dec. 31, 1992, now abandoned.

TECHNICAL FIELD

This invention relates to phosphors and methods of making them. Inparticular, it relates to methods of making electroluminescent phosphorsby providing an inorganic intercalation compound characterized by anatomic structure interspersed with vacant spaces of sufficient size toaccommodate foreign atoms or molecules within them; doping the inorganicintercalation compound with selected activator ions which, when excitedby an electric field or other exciting radiation, are capable ofluminescent emission; and interposing selected conductive materials intothe vacant spaces of the inorganic intercalation compound. It alsorelates to electroluminescent phosphors and electroluminescent lampsmade by this method.

BACKGROUND ART

Electroluminescent lamps typically provide approximately 30foot-lamberts of illumination and are thus suitable for variouslow-intensity illumination applications, such as decorative lighting,egress lighting, cockpit and dashboard display panels, and membraneswitches. They have also been used as backlighting sources for liquidcrystal display (LCD) devices. However, most LCD applications, includingblack/white and color LCD displays and high definition displays, requiregreater backlighting illumination than electroluminescent lamps canprovide. Furthermore, most electroluminescent lamps have poormaintenance characteristics: they typically degrade to about half theirinitial brightness within 2000 hours of operation.

Fluorescent lamps, which provide between 2000 and 4000 foot-lamberts ofillumination, have been used as illumination sources for these LCDdisplay devices. However, when used in LCD display applications,fluorescent lamps have their own disadvantages. For example, they arebulky. Being made of glass, they are also fragile and thus are unable towithstand rugged environments; if broken, they may release small amountsof mercury. They also do not operate at temperatures below -20° C. Incontrast, electroluminescent lamps do not have the disadvantages of sizeand construction that fluorescent lamps have. They are quite small andthin, light in weight, extremely rugged, and they can operate attemperatures well below -20° C.

To be useful in LCD backlighting applications, electroluminescentphosphors must emit in narrow bands of the blue, green and red zones ofthe visible spectrum. Specifically, the blue emission wavelength shouldpreferably be between 460-470 nm, the green emission wavelength shouldpreferably be between 535-545 nm, and the red emission wavelength shouldpreferably be between 610-650 nm.

One electroluminescent phosphor which meets the above-described blueemission color requirements for LCD backlighting applications is ablue-emitting copper-activated zinc sulfide phosphor, ZnS:Cu. Zincsulfide phosphors and methods of making them are described in U.S. Pat.Nos. 2,807,587 to Butler et al., 3,031,415 to Morrison et al., 3,031,416to Morrison et al., 3,152,995 to Strock, 3,154,712 to Payne, 3,222,214to Lagos et al., 3,657,142 to Poss, and 4,859,361 to Reilly et al., allof which are assigned to the assignee of the instant invention. However,notwithstanding their emission color characteristics, none of theseelectroluminescent zinc sulfide phosphors, nor any otherelectroluminescent phosphors, are sufficiently bright for use in mostLCD backlighting applications or high definition display devices.

It would be an advantage in the art to provide an electroluminescentphosphor having improved luminance and maintenance for use in LCD andhigh definition display devices, and a method of making the phosphor.

SUMMARY OF THE INVENTION

It is an object of this invention to obviate the disadvantages of theprior art.

It is another object of this invention to provide an electroluminescentphosphor having substantially increased luminance and maintenance overprior art electroluminescent phosphors.

It is another object of this invention to provide a method of making anelectroluminescent phosphor having substantially increased luminance andmaintenance over prior art electroluminescent phosphors.

These objects are accomplished, in one aspect of the invention, by anelectroluminescent phosphor which comprises an inorganic intercalationcompound characterized by an atomic structure interspersed with vacantspaces of sufficient size to accommodate foreign atoms or moleculeswithin them, wherein the inorganic intercalation compound has been (1)doped with selected activator ions which are capable of luminescentemission when excited by an electric field or other exciting radiation,and (2) interposed with conductive organic polymers or other conductivematerial within the vacant spaces of the doped inorganic intercalationcompound.

These objects are accomplished, in another aspect of the invention, by amethod of making an electroluminescent phosphor, comprising the stepsof: providing an inorganic intercalation compound characterized by anatomic structure interspersed with vacant spaces of sufficient size toaccommodate foreign atoms or molecules within them; doping the inorganicintercalation compound with selected activator ions which are capable ofluminescent emission when excited by an electric field or other excitingradiation to obtain a doped inorganic intercalation compound; andinterposing selected conductive materials into the vacant spaces of thedoped inorganic intercalation compound.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram representing the approximate atomicstructure of fluorophlogopite, an inorganic intercalation compound.

FIG. 2 is a schematic diagram representing the approximate atomicstructure of fluorophlogopite which has been doped with manganeseactivator ions and interposed with polypyrrole polymers, the monomers ofwhich were previously introduced into the interlamellar Van der Waalsspaces of the fluorophlogopite.

FIG. 3 is a schematic representation of the structure of anelectroluminescent lamp.

BEST MODE FOR CARRYING OUT THE INVENTION

For a better understanding of the present invention, together with otherand further objects, advantages and capabilities thereof, reference ismade to the following specification and appended claims.

Electroluminescent phosphors having substantially increased luminanceover that of prior art electroluminescent phosphors may be made bydoping an inorganic intercalation compound, characterized by an atomicstructure interspersed with vacant spaces of a sufficient size toaccommodate foreign atoms or molecules within them, with selectedactivator ions which are capable of luminescent emission when excited byan electric field or other exciting radiation. Conductive materials,such as, for example, mercury, or selected organic monomers which becomeconductive when polymerized, may then be interposed into the vacantspaces of the atomic structure of the doped inorganic intercalationcompound. The organic monomers may then be polymerized in situ to formconductive polymers therein which may effect an expansion of theconductive volume of the doped inorganic intercalation compound. Theresult is an electroluminescent phosphor which may have substantiallygreater luminance than that of prior art electroluminescent phosphors.

Inorganic intercalation compounds are known. They generally have anatomic structure characterized by the presence of ionically bonded atomsin substructures interspersed with vacant spaces which are sufficientlylarge to accommodate foreign atoms or molecules within them.Intercalation compounds are generally of three types: lamellar, orlayered, compounds; channel-type compounds; and cage-type compounds.

In lamellar intercalation compounds the atomic substructures compriselayers, or lamellae, of ionically bonded inorganic atoms. The lamellaethemselves are bonded together by relatively weak forces, known as Vander Waals forces. The relatively weak Van der Waals forces between thelamellae permit the entry of foreign atoms or molecules into the spaces(hereinafter referred to as "Van der Waals spaces") between thelamellae. The Van der Waals spaces in lamellar intercalation compoundsare large enough to accommodate foreign atoms or molecules which may beintroduced by various methods, such as, for example, ion exchange,diffusion, acid-base reactions and electrochemical reactions.

In channel-type intercalation compounds the atomic substructurescomprise zones of ionically bonded inorganic atoms which areinterspersed with networks of vacant channels which are sufficientlylarge to accommodate foreign atoms or molecules within them. Incage-type intercalation compounds the atomic substructures of ionicallybonded atoms are interspersed with vacant holes, or cages, which aresufficiently large to accommodate foreign atoms or molecules withinthem. The vacant channels or cages are interspersed throughout theatomic structure of the intercalation compound.

The lamellae of a crystal of a lamellar inorganic intercalation compoundare generally parallel to the long axis of the crystal, whereas thechannels of a channel-type inorganic intercalation compound crystal, andthe cages or holes of a cage-type crystal, may be more randomlyoriented.

Suitable inorganic intercalation compounds include vermiculites, micas,fluoromicas, xerogels (such as, for example, vanadium pentoxide made bysol-gel processing), iron oxychloride, zirconium phosphates, andzeolites.

Vermiculite is a lamellar intercalation compound which has the idealizedgeneral formula

(Ca,Mg)_(x/2) (Mg,Fe,Al)₃ [(Al,Si)₄ O₁₀ ](OH)₂,

where the first listed calcium and magnesium ions are exchangeablecations which reside in the interlamellar Van der Waals spaces, and x isany integer. Mica is another type of lamellar intercalation compoundhaving the general idealized formula M_(x) (Si₄ O₁₀)(OH)₂, where M is anexchangeable cation, typically aluminum or magnesium, and x is anyinteger. Fluoromicas, which are similar in structure to vermiculites,have the general idealized formula (Ca,Mg)_(x/2) (Mg,Fe,Al)₃ [(Al,Si)₄O₁₀ ]F₂. An example of a fluoromica is fluorophlogopite, which has thegeneral formula KMg₃ (Si₃ Al)O₁₀ F₂.

FIG. 1 is a schematic representation of the lamellar atomic structure offluorophlogopite. Fluorophlogopite 10 is comprised of atoms of oxygen18, aluminum 20, silicon 22, magnesium 24 and fluorine 26 which areionically bonded together into atomic substructures 12. Between theatomic substructures 12 are Van der Waals spaces 14 in which residepotassium atoms 16.

Zirconium phosphates have the general formula Zr(MPO₄)₂.xH₂ O, where Mis a monovalent exchangeable cation and x is any integer.

Zeolites are crystalline aluminosllicate intercalation compounds havingan atomic structure which is interspersed with networks of channelsand/or cages filled with exchangeable cations and water. Zeolites havethe general formula M_(x) D_(y) (Al_(x+2y) Si_(n-)(x+2y) O₂ n).mH₂ O,where M is a monovalent or divalent exchangeable cation and x and y areany integers. The channels and/or cages within the zeolite structure aresufficiently large to accommodate foreign atoms or molecules withinthem, including organic polymers, which may be introduced by thepreviously described methods.

The inorganic intercalation compounds are first doped with selectedactivator ions which are capable of luminescent emission undercathodoluminescent, fluorescent, x-ray or electroluminescent excitation.The following table lists several activator ions suitable for doping,along with the probable emission color from each. The precise emissioncolors obtained will depend on the site occupied by the particularactivator ion in the lattice of the inorganic intercalation compound.

                  TABLE 1                                                         ______________________________________                                        ACTIVATOR ION DOPANTS                                                         AND THEIR EMISSION COLORS                                                     RED           GREEN        BLUE                                               ______________________________________                                        Mn.sup.+2     Mn.sup.+2    Sb.sup.+3                                          Mn.sup.+4     Eu.sup.+2    Ti.sup.+4                                          Fe.sup.+3     Tb.sup.+3    Sn.sup.+2                                          Eu.sup.+3                  Tm.sup.+3                                          Sm.sup.+3                  Eu.sup.+2                                          Cr.sup.+3                  Ce.sup.+3                                          ______________________________________                                    

The activator ions may be doped into the atomic lattice of the inorganicintercalation compound by several methods, including high-temperaturesolid-state synthesis (generally in excess of 1000° C.), hydrothermalsynthesis, wet-chemical procedures and low-temperature procedures. Theactivator ions generally occupy lattice sites within the atomicstructure of the inorganic intercalation compound. For example, when aninorganic intercalation compound, such as fluorophlogopite, is dopedwith manganese ions, the manganese ions replace a small fraction of themagnesium ions in the fluorophlogopite atomic structure.

Fluxing agents, such as, for example, sodium chloride or bariumchloride, may be used during the doping process, although they are notgenerally required.

The doped inorganic intercalation compound may be excited with, forexample, cathode ray or ultraviolet radiation (since mostelectroluminescent materials are also cathodoluminescent and/orphotoluminescent), to determine its luminescence intensity and itsemission color. Luminescence intensity of the doped inorganicintercalation compound may be optimized by varying the amounts of thedesired dopant ions.

Conductive materials, such as mercury, or selected organic monomerswhich are capable of becoming conductive when polymerized, such asaniline and pyrrole, may then be introduced into the vacant spaces ofthe atomic structure of the doped inorganic intercalation compound. Iforganic monomers are used, they may then be polymerized in situ to formconductive organic polymers. The conductive polymers may be formed inseveral ways, including the single polymerization of each organicmonomer, the successive, multiple polymerizations of each organicmonomer, and the addition of functional groups to an organic monomer toeffect cross-linking of the monomer chains. The last two methods,successive polymerization and the addition of functional groups to themonomer, may effect a swelling of the polymer-filled spaces in theinorganic intercalation compound.

FIG. 2 is a schematic representation of fluorophlogopite 10 which hasbeen doped with manganese ions 28 and interposed with pyrrole monomers30 into the Van der Waals spaces 14.

The following equations are illustrative of the chemical reactions thatoccur during synthesis of an electroluminescent phosphor according tothe method of this invention. In this illustrative example, theinorganic intercalation compound is a vermiculite and the conductivepolymer is polyaniline. ##STR1##

In Equation [1], a vermiculite having sodium as the exchangeablemonovalent cation occupying the Van der Waals spaces is contacted withacetic acid at a temperature of less than 60° C. Monovalent hydrogenions, H⁺ (or hydronium ions H₃ O⁺), replace the sodium ions in the Vander Waals spaces of the vermiculite.

In Equation [2], the vermiculite containing hydrogen or hydronium as theexchangeable monovalent cation is contacted with a copper chloridesolution. In the presence of copper chloride, some of the monovalentions in the vermiculite are replaced with divalent copper ions.

In Equation [3], the vermiculite containing both monovalent hydrogen (orhydronium) ions and divalent copper ions is reacted with aniline. Theaniline enters the Van der Waals spaces of the vermiculite in anacid-base reaction with the monovalent cation. In the presence of thedivalent copper ions the aniline will polymerize to form conductivepolyaniline in the Van der Waals spaces of the vermiculite.

The result of polymerization of selected organic monomers will be theinterposition of conductive polymers into the vacant spaces of theintercalation compound. Under certain polymerization conditions, anexpansion of the conductive volume of the intercalation compound mayalso occur. When lamellar intercalation compounds, such as vermiculites,are used, polymerization of the organic monomer will occur in theinterlamellar Van der Waals spaces of the intercalation compound. Whenchannel-type or cage-type intercalation compounds, such as zeolites, areused, polymerization of the organic monomer will occur within the vacantchannels or cages interspersed throughout the atomic structure of theintercalation compound.

When particles of an electroluminescent phosphor made by the method ofthis invention are exposed to an electric field, the electric field willconcentrate across the insulating portions of the particles whichcontain the activator ions capable of luminescent emission, since theconductive portions will not support an electric field. The activatorions will luminesce very efficiently when exposed to a highlyconcentrated electric field.

To increase the conductive volume of the doped inorganic intercalationcompound and thereby increase luminance, particularly in lamellarintercalation compounds characterized by the presence of Van der Waalsspaces, polymerization of the organic monomer in three dimensions may bedesirable. For example, to effect polymerization of aniline in threedimensions, some of the hydrogen atoms on the phenyl group (C₆ H₅) maybe replaced with a carboxylic acid group (COOH). Alternatively, some ofthe hydrogen atoms of the phenyl group of the aniline molecule may bereplaced with both carboxylic acid and amine groups (NH₂) to crosslinkthe conductive polymer chains through the formation of peptide linkages.The conductivity of the polymer should not be adversely affected by thesubstitution of these alternative functional groups in the polymerbackbone. Alternatively, swelling of the conductive volume of the dopedinorganic intercalation compound may be achieved by successivemonomer-to-polymer conversions within the vacant spaces of theintercalation compound.

FIG. 3 is a schematic representation of the structure of anelectroluminescent lamp 60. A conductive substrate material, such asaluminum or graphite, forms a first electrode 62 of the lamp 60, while atransparent conductive film, such as indium tin oxide, forms a secondelectrode 64. Sandwiched between the two conductive electrodes 62 and 64are two additional layers of dielectric material 70 which can be, forexample, cyanoethyl cellulose or cyanoethyl starch. Adjacent to thefirst electrode 62 is a layer of dielectric material 70 in which may beembedded particles of a ferroelectric material 72. Adjacent to thesecond electrode 64 is a layer of dielectric material 70 in which may beembedded particles of the electroluminescent phosphor 74 of thisinvention.

The luminance of an electroluminescent phosphor made by the method ofthis invention may be equivalent to that obtained from commerciallyavailable fluorescent lamps.

The following non-limiting examples are presented.

EXAMPLES 1-6

Green-emitting titanium-activated fluorophlogopite phosphor sampleshaving the general formula KMg₃ (Si₃ Al)O₁₀ F₂ :Ti were prepared byblending the following raw materials: 9.40 grams of potassium carbonate,K₂ CO₃ ; 20.39 grams of aluminum oxide, Al₂ O₃ ; 48.37 grams ofmagnesium oxide, MgO; 64.04 grams of silicon dioxide, SiO₂ ; 29.51 gramsof potassium hexafluorosilicate, K₂ SiF₆ ; and varying amounts (0 mole;0.320 gram, or 0.01 mole; 0.959 gram, or 0.03 mole; 1.278 grams, or 0.04mole; 1.598 grams, or 0.05 mole; and 3.995 grams, or 0.125 mole) oftitanium dioxide, TiO₂. All raw materials were at least certified gradepurity and are commercially available. These raw materials were blendedin a mechanical mixer for 20-30 minutes until uniformly mixed. Themixture was charged to an alumina crucible and fired in air at 1200° C.for 12 hours. The fired cakes were then cooled, pulverized, screenedand, if necessary, washed in deionized water. Scanning ElectronMicroscopy (SEM) techniques revealed that the resulting phosphorparticles had a platelet morphology. X-ray diffraction data indicatedthe formation of single-phase fluorophlogopite. The phosphor sampleswere evaluated for luminescence under cathode ray excitation andproduced a green emission with a maximum peak at about 540 nm. A weakred emission with a peak at about 720 nm was also observed. Optimumluminescence was obtained at 0.03 mole titanium per mole offluorophlogopite.

EXAMPLES 7-15

Red-emitting manganese-activated fluorophlogopite phosphor sampleshaving the general formula KMg₃ (Si₃ Al)O₁₀ F₂ :Mn were prepared byblending the following raw materials: 9.40 grams of potassium carbonate,20.39 grams of aluminum oxide, 48.37 grams of magnesium oxide, 64.04grams of silicon dioxide, 29.51 grams of potassium hexafluorosllicate,and varying amounts (0 mole; 0.920 gram, or 0.02 mole; 1.379 grams, or0.03 mole; 1.839 grams, or 0.04 mole; 2.299 grams, or 0.05 mole; 2.759grams, or 0.06 mole; 3.219 grams, or 0.07 mole; 3.678 gram, or 0.08mole; and 4.598 grams, or 0.10 mole) of commercially available manganesecarbonate, MnCO₃. These raw materials were blended in a mechanical mixerfor 20-30 minutes until uniformly mixed. The mixture was charged to analumina crucible, which was placed into a larger alumina cruciblecontaining graphite pellets (to produce a mildly reducing atmosphere)and covered, and fired at 1200° C. for 12 hours. The fired cakes werethen cooled, pulverized, screened and, if necessary, washed in deionizedwater. Scanning electron microscopy techniques revealed that theresulting phosphor particles had a platelet morphology. X-raydiffraction data indicated the formation of single-phasefluorophlogopite. The phosphor samples were evaluated for luminescenceunder cathode ray excitation and produced a red emission with a maximumpeak at about 700 nm. Optimum luminescence was obtained at 0.04 mole ofmanganese per mole of fluorophlogopite.

EXAMPLES 16-21

Green-emitting terbium-activated fluorophlogopite phosphor sampleshaving the general formula KMg₃ (Si₃ Al)O₁₀ F₂ :Tb were prepared byblending the following raw materials: 4.7 grams of potassium carbonate,10.2 grams of aluminum oxide, 24.19 grams of magnesium oxide, 32.02grams of silicon dioxide, 14.75 grams of potassium hexafluorosilicate,and varying amounts (0 mole; 0.216 gram, or 0.005 mole; 0.432 gram, or0.01 mole; 0.864 gram, or 0.02 mole; 1.730 grams, or 0.04 mole; and 2.16grams, or 0.05 mole) of commercially available terbium fluoride, TbF₃.These raw materials were blended in a mechanical mixer for 20-30 minutesuntil uniformly mixed. The mixture was charged to an alumina cruciblewhich was then placed into a larger alumina crucible containing graphitepellets (to produce a mildly reducing atmosphere) and covered, and firedat 1200° C. for 12 hours. The fired cakes were then cooled, pulverized,screened and, if necessary, washed in deionized water. Scanning electronmicroscopy techniques revealed that the resulting phosphor particles hada platelet morphology. X-ray diffraction data indicated the formation ofsingle-phase fluorophlogopite. The phosphor samples were evaluated forluminescence under cathode ray excitation and produced a characteristicTb³⁺ green emission with a maximum peak at about 540 nm. Optimumluminescence was obtained at 0.01 mole of terbium per mole offluorophlogopite.

EXAMPLES 22-26

Ultraviolet-to-blue-emitting titanium-activated crystalline alphazirconium phosphate phosphor samples having the general formula Zr_(1-x)Ti_(x) (HPO₄)₂.H₂ O were prepared as follows:

    ______________________________________                                        zirconium oxychloride                                                         octahydrate, ZrOCl.sub.2.8H.sub.2 O                                                            titanium source                                              ______________________________________                                                         0       mole                                                 0.98 mole (47.21 grams)                                                                        0.02    mole (1.238 grams)                                                            titanium sulfate                                                              hydrate                                              0.96 mole (46.404 grams)                                                                       0.04    mole (1.764 grams)                                                            ammonium titanyl                                                              oxalate hydrate                                      0.95 mole (45.92 grams)                                                                        0.05    mole (2.205 grams)                                                            ammonium titanyl                                                              oxalate hydrate                                      0.92 mole (44.47 grams)                                                                        0.08    mole (3.528 grams)                                                            ammonium titanyl                                                              oxalate hydrate                                      ______________________________________                                    

The titanium source was either titanium sulfate hydrate, Ti(SO₄)₂.xH₂ O,or ammonium titanyl oxalate hydrate, (NH₄)₂ TiO(C₂ O₄)₂.H₂ O, bothcommercially available. Any titanium source which is soluble in eitherwater or acid may be used. The zirconium oxychloride octahydrate,commercially available, was dissolved in 240 milliliters of deionizedwater. A second solution was prepared by dissolving the titanium sourcein 15 to 20 milliliters of deionized water. The two solutions were thencombined in a polypropylene or Teflon beaker. To this solution wasadded, with stirring, 36 milliliters of 49% hydrofluoric acid, HF. Next,207 milliliters of 85% phosphoric acid, H₃ PO₃, was slowly added to thesolution, with stirring, over a 10-minute period using a separatingfunnel. The amounts of both the hydrofluoric acid and phosphoric acidrepresented an excess of the stoichiometric amounts. Nitrogen gas, N₂,was then bubbled through the resulting solution over a period of 66hours to evaporate hydrogen fluoride gas and precipitate crystallineparticles of titanium-activated alpha zirconium phosphate. Scanningelectron microscopy techniques revealed that the resulting phosphorparticles had a platelet morphology. X-ray diffraction data indicatedthe formation of single-phase crystalline alpha zirconium phosphatehaving a layered atomic structure. The phosphor samples were evaluatedfor luminescence under cathode ray excitation and produced anultraviolet-to-blue emission with a maximum peak at about 350 nm.

While there have been shown what are at present considered to be thepreferred embodiments of the invention, it will be apparent to thoseskilled in the art that various changes and modifications can be madeherein without departing from the scope of the invention as defined bythe appended claims.

We claim:
 1. A green-emitting titanium-activated fluorophlogopitephosphor having the general formula KMg₃ (Si₃ Al)O₁₀ F₂ :Ti.
 2. Agreen-emitting titanium-activated fluorophlogopite phosphor according toclaim 1 wherein said phosphor is activated by titanium in an amount ofup to about 0.125 mole per mole of fluorophlogopite phosphor.
 3. Agreen-emitting titanium-activated fluorophlogopite phosphor according toclaim 1 wherein said phosphor is activated by titanium in an amount of0.03 mole per mole of fluorophlogopite phosphor.
 4. A red-emittingmanganese-activated fluorophlogopite phosphor having the general formulaKMg₃ (Si₃ Al)O₁₀ F₂ :Mn.
 5. A red-emitting manganese-activatedfluorophlogopite phosphor according to claim 4 wherein said phosphor isactivated by manganese in an amount of up to about 0.10 mole per mole offluorophlogopite phosphor.
 6. A red-emitting manganese-activatedfluorophlogopite phosphor according to claim 4 wherein said phosphor isactivated by manganese in an amount of 0.04 mole per mole offluorophlogopite phosphor.
 7. A green-emitting terbium-activatedfluorophlogopite phosphor having the general formula KMg₃ (Si₃ Al)O₁₀ F₂:Tb.
 8. A green-emitting terbium-activated fluorophlogopite phosphoraccording to claim 7 wherein said phosphor is activated by terbium in anamount of up to about 0.05 mole per mole of fluorophlogopite phosphor.9. A green-emitting terbium-activated fluorophlogopite phosphoraccording to claim 7 wherein said phosphor is activated by terbium in anamount of 0.01 mole per mole of fluorophlogopite phosphor.
 10. Ablue-emitting titanium-activated crystalline alpha zirconium phosphatephosphor having the general formula Zr_(1-x) Ti_(x) (HPO₄)₂.H₂ O.
 11. Ablue-emitting titanium-activated crystalline alpha zirconium phosphatephosphor according to claim 10 wherein x is from 0.02 to 0.08.